California Institute of Technology
Einstein Papers Project




In Memoriam: Issachar Unna

Issachar Unna, 2016 at EPP Retreat

The EPP mourns the passing of our collaborator Issachar Unna, Professor Emeritus of Physics, Hebrew University, who was an editor, researcher, and friend.

Unna’s expertise in nuclear physics, quantum theory, history of modern physics, and the teaching of physics, coupled with his intimate knowledge of German, informed his meticulous reviews of the final drafts for Volumes 7, 9, 10, and 12 of The Collected Papers of Albert Einstein, and his contributions as Associate Editor on Volumes 13, 14, and 15.

A Jerusalem-born bibliophile, Unna was a passionate popularizer of science. He edited Hebrew translations of children’s books on Einstein, and of Einstein’s anthology Ideas and Opinions. In Israel he was a generous host to visiting colleagues. In Pasadena, he was an affable guest over the span of two decades. He will be missed by all of us. 10-15-2021

Photo Credit: Emily Araújo

Berlin studio portrait Einstein at age 50

The Einstein Papers Project at Caltech has released the 16th volume of its massive scholarly collection of Albert Einstein's scientific and nonscientific writings and correspondence. The volume covers the period from June 1927 to May 1929 and contains 1,600 letters by and to Einstein, many more than contained in previous volumes. This is due in part to the fact that Einstein turned 50 on March 14, 1929 and received a flood of congratulatory wishes. Some of the documents in the new volume pertain to a birthday present Einstein cherished the most: a single-cabin sailboat, named Tümmler, which means porpoise in German.

For his 50th birthday, Einstein had only one wish, according to Diana Kormos-Buchwald, Caltech's Robert M. Abbey Professor of History and director of the Einstein Papers Project: "He wanted to avoid the press, the visitors, the fanfare, and the tributes. He escaped Berlin for the countryside," she says.

The new volume also includes scientific papers, poems, speeches, obituaries, and book reviews. In his writings on political and social issues, Einstein advocates for domestic legislative reform, gay and minority rights, European rapprochement, and conscientious objection to military service. During the time covered by this volume, he hired Helen Dukas as his assistant; she worked with Einstein until the end of his life and was instrumental in the preservation of his written legacy. Continue reading article on Caltech News.

Photo Credit: Greg Berger for the Manhattan Rare Book Company, New York


CPAE Volume 16 Cover

The Collected Papers of Albert Einstein, Volume 16: The Berlin Years / Writings and Correspondence / June 1927 - May 1929

Princeton University Press is pleased to announce the publication of The Collected Papers of Albert Einstein, Volume 16: The Berlin Years / Writings and Correspondence / June 1927 – May 1929 (North American publication, June 22, 2021; UK publication, July 13, 2021). Publishing in tandem are two editions: a cloth Documentary Edition – a definitive scholarly edition of the correspondence and papers of Albert Einstein – and a paperback Translation Supplement, a selection of translated non-English texts that appearing in Volume 16. Both editions are edited by Diana Kormos Buchwald, Ze’ev Rosenkranz, József Illy, A. J. Kox, Daniel J. Kennefick, Dennis Lehmkuhl, Tilman Sauer, and Jennifer Nollar James.

During the period covered by Volume 16, Einstein aims to discover whether one can derive the electron’s equations of motion directly from the field equations of general relativity, and he embarks on a new approach to unified field theory founded on teleparallel geometry. On these topics, he engages in exchanges with J. Grommer, C. Lanczos, and particularly with C. H. Müntz, and corresponds with mathematicians like R. Weitzenböck and É. Cartan. Einstein attends what will be considered a historic 1927 Solvay Conference where the new quantum mechanics is discussed, but in fact he makes very few remarks.

In an important prelude to his eventual emigration to the United States, he is invited in September 1927 to accept a research professorship at Princeton University. Despite the sudden onset of a severe heart ailment in 1928, followed by an almost year-long period of convalescence, Einstein maintains a sustained engagement with scientific work, correspondence, and social and political issues. He publishes many articles and interviews designed for a popular audience and continues various technical preoccupations, including publishing a patent for a novel “people’s” refrigerator and being intimately involved in the design of his famous sailboat.

Einstein advocates for domestic legislative reform, gay and minority rights, European rapprochement, and conscientious objection to military service. He resigns from his positions at the Hebrew University. He also tries to avoid the fanfare marking his fiftieth birthday in March 1929 yet is “buried under a paper avalanche” from the tributes.
His hiring of Helen Dukas as his assistant, who accompanies Einstein to the end of his life, is of great significance for the ultimate preservation of his written legacy.

About the Editors

At the California Institute of Technology, Diana Kormos Buchwald is the Robert M. Abbey Professor of History; Ze’ev Rosenkranz is senior editor; József Illy and A. J. Kox are senior editors and visiting associates in history; Daniel J. KennefickDennis Lehmkuhl, and Tilman Sauer are scientific editors; and Jennifer Nollar James is associate editor.

About the Collected Papers of Albert Einstein
The Collected Papers of Albert Einstein is the ongoing publication of Einstein’s archive of more than 30,000 unique documents. The series is published by Princeton University Press and edited by The Einstein Papers Project at the California Institute of Technology, with the assistance of The Albert Einstein Archives at Hebrew University of Jerusalem. Follow the project on Twitter @EinsteinPapers

Publication Details

The Collected Papers of Albert Einstein, Volume 16: The Berlin Years / Writing and Correspondence / June 1927 – May 1929 (Documentary Edition)

June 22, 2021 (US); July 13, 2021 (UK)
$200 / £164.00
ISBN: 9780691216812 
Pages: 1128
Size 7.5 x 10
Illustrations: 28 b/w

The Collected Papers of Albert Einstein, Volume 16: The Berlin Years / Writing and Correspondence / June 1927 – May 1929 (Translation Supplement)

June 22, 2021 (US); July 13, 2021 (UK)
$200 / £164.00
ISBN: 9780691216829
Pages: 528
Size 7.5 x 10


Summer Arrivals: Our Latest Volume and New Versions of Previous Volumes

CPAE Volume 16 cover and title page

We, who have had the chance to venture into our campus office, have had the joy of holding and paging through advance copies of our latest volume: The Collected Papers of Albert Einstein, Volume 16: The Berlin Years: Writings & Correspondence, June 1927 - May 1929. The translation and documentary editions are pictured here with the title page.

The crunch time for Volume 16, when sets of page proofs were exchanged with our copy editor and the press, took place under lockdown. Like many around the globe we adapted to a new work flow while missing workmates' camraderie and visits from international colleagues, who typically come to work alongside us, at Caltech, as our shared deadlines clustered ever closer together. The rigorous editing of a 1,000+ page manuscript in English and German, replete with 540 full-text documents and 1,164 abstracts, equations, facsimile reproductions and all the vital front and backmatter, such as introduction and index, was done by the end of 2020. A few last minute corrections on our end and a paper shortage on the printer's end, working from home on Volume 16 will hold a special place in the project's memory. CPAE Volume 16 will be released in the US on June 22 and in the UK and EU on July 13, 2021. Not ones to rest on our laurels, we are happy to report that research for Volume 17 is underway and keeping us on our toes.

CPAE Volumes 11-13 Chinese Simplified

Similarly committed, while Princeton University Press worked with us throughout the pandemic on our latest and future volumes, they produced with Hunan Science and Technology Press the beautiful, simplified Chinese, editions of CPAE Volumes 11, 12 and 13 pictured here. Translations of Volumes 1-10 are in progress for release at a later date.


headshot of Diana Kormos Buchwald

We extend our warmest congratulations to the EPP Director and General Editor. Diana Kormos Buchwald, Robert M. Abbey Professor of History at Caltech, was elected to The American Philosophical Society. The oldest learned society in the United States, the American Philosophical Society was founded in 1743 by Benjamin Franklin for the purpose of “promoting useful knowledge.” Society membership is unique for the diverse range of disciplines represented within its ranks.

The Society has 1,011 elected members, 847 resident members and 164 international members from more than two dozen foreign countries. Only 5,746 members have been elected since 1743. Professor Kormos Buchwald is the thirty-fifth Caltech researcher distinguished with election to the Society. The EPP's raison d'être, Albert Einstein, was elected to the American Philosophical Society in 1930.


Commemorations: Einstein's Birthday & His First Visit to the United States

screenshot from PUP's Ideas blog featuring Kennefick's article

screenshot of Dan Falk's article on Smithsonian Magazine website

Einstein's 142nd birthday fell on March 14, 2021. Among various Pi Day + AE tributes, the occasion was also marked with a delightful post written by Daniel Kennefick, EPP Scientific Editor, for Princeton University Press' blog. Happy 40th, Einstein! is in the "History of Science and Knowledge" section of PUP: Ideas. Einstein's fortieth birthday was in 1919. Kennefick writes "unbeknownst to Einstein, this birthday would be the last one he could enjoy in comfortable obscurity. Events were in motion that would make him an international celebrity literally overnight before the year was out."

This April marks the centenary of Einstein's first visit to the United States. On April 2, 1921, Einstein arrived at the port of New York. The ensuing fanfare and his whistle stop tour of a wide swath of the United States is described in detail in Smithsonian Magazine. Canadian science journalist, Dan Falk interviewed EPP General Editor and Director Diana Kormos Buchwald and EPP Assistant Director and Senior Editor Ze'ev Rosenkranz for the piece. Read Falk's insightful article on the Smithsonian website: One Hundred Years Ago, Einstein Was Given a Hero’s Welcome by America’s Jews.


English Release: A.J. Kox and H.F. Schatz's Biography of Lorentz

Image includes book covers of Lorentz biographies published by Balans and OUP

EPP Senior Editor A. J. Kox and EPP translator H. F. Schatz's biography A Living Work of Art: The Life and Science of Hendrik Antoon Lorentz was released by Oxford University Press in mid-February. It follows the original Dutch release by Balans published in 2019. Kox's other works on Lorentz include the two volume series he edited for Springer. The Scientific Correspondence of H.A. Lorentz. Volume 2, The Dutch Correspondents was released in 2018. A long-time Senior Editor at the EPP he has worked on fifteen of our sixteen volumes.


Coming Soon: CPAE, Volume 16

Image includes 1928 studio portrait of Albert Einstein, courtesy Greg Berger for The Manhattan Rare Book Company, NY

EPP editors eagerly await the release of the next book in our series: The Collected Papers of Albert Einstein, Volume 16. The book contains 540 original language, full text items and 1,164 items in abstract, from the eighteen month period of June 1927 through May 1929. Twenty-eight additional full text items are included in the volume; these are texts that would have been published in an earlier volume but have only come to light in recent years. The materials are presented chronologically, with correspondence and writings contextualized with thorough annotation. Thirteen appendixes round out the book, along with other crucial front and back matter including: an introduction, illustrations, chronology, and a robust index. Along with the described documentary edition, a companion translation volume will be released at the same time. Volumes 1 - 15 of the CPAE are online and open access: